Method for operating a lidar system comprising a comparison between electric charge of receiving elements with at least one eye-safety-charge-threshold and performing an eye safety procedure

Abstract

A method for operating a LiDAR system, in particular for operating a LiDAR system of a vehicle, a software, a LiDAR system, a driver assistance system and a vehicle are de- scribed. In the method at least one electromagnetic scanning signal is sent into a moni- toring area by use of at least one transmitting device of the LiDAR system. At least one receiving element of a receiving device of the LiDAR system is activated to receive elec- tromagnetic echo signals, if any, that originate from electromagnetic scanning signals that are reflected in the monitoring area. Electric charge (eA, eB) of the at least one receiving element that is generated by the received electromagnetic echo signals is accumulated. After at least one predetermined time interval the accumulated electric charge (eA, eB) of the at least one receiving element is compared with at least one predetermined eye- safety-charge-threshold (Theye). If the comparison shows that the at least one accumu- lated electric charge (eA, eB) has reached the at least one eye-safety-charge-threshold (Theye), an eye safety procedure is performed.

Description

[0001] 1 / 27 2022PF00195

[0002] Description

[0003] Method for operating a LiDAR system comprising a comparison between electric charge of receiving elements with at least one eye-safety-charge-threshold and performing an eye safety procedure

[0004] Technical Field

[0005] The present invention relates to a method for operating a LiDAR system, in particular for operating a LiDAR system of a vehicle, in which at least one electromagnetic scanning signal is sent into a monitoring area by use of at least one transmitting device of the LiDAR system, at least one receiving element of a receiving device of the LiDAR system is activated to receive electromagnetic echo signals, if any, that originate from electromagnetic scanning signals that are reflected in the monitoring area.

[0006] Further, the invention relates to software that comprises at least a portion of the means for carrying out a method for operating a LiDAR system, in particular for operating a LiDAR system of a vehicle.

[0007] Furthermore, the invention relates to a LiDAR system, in particular a LiDAR system for a vehicle, that comprises at least one transmitting device for sending electromagnetic scanning signals, at least one receiving device with at least one receiving element for receiving electromagnetic signals.

[0008] Moreover, the invention relates to a driver assistance system with at least one LiDAR system, the LiDAR system comprises at least one transmitting device for transmitting electromagnetic scanning signals, at least one receiving device with at least one receiving element for receiving electromagnetic signals.

[0009] In addition, the invention relates to a vehicle with at least one LiDAR system, the LiDAR system comprises at least one transmitting device for transmitting electromagnetic scanning signals, at least one receiving device with at least one receiving element for receiving electromagnetic signals.

[0010] State of Technology 2 / 27 2022PF00195

[0011] From George M. Williams, Jr. “Optimization of eyesafe avalanche photodiode lidar for automobile safety and autonomous navigation systems,” Opt. Eng. 56(3), 031224 (2017), optimization of eyesafe avalanche photodiode lidar for automobile safety and autonomous navigation systems is known. A lidar device shoots out rapid bursts of short pulsed infrared laser light, in a very similar fashion to sonar with sound waves or LiDAR with radio waves. The light travels toward whatever object is in its path, then reflects back toward the device. Since the speed of light is well known, lidar sensors can determine the range to a target by measuring the time it takes for the light to return to the origin. To ensure the laser is fully eyesafe (class 1 M, IEC / EN 60825), the maximum pulse energy and pulse-repetition rate must be limited, and an appropriate beam expander must be used. At high repetition rates (i.e., above 55 kHz), the emission is considered as a continuous-wave source with a power level equal to the average power emitted by the transmitter. The safety requirements on these laser transmitters make it difficult to cover a large FOR, and expanding the laser beam to reduce the power flux density increases system size and weight.

[0012] It is an objective of the invention to provide a method, a software, a LiDAR system, a driver assistance system and a vehicle of the type mentioned above in which the detection range of the LiDAR system can be improved while maintaining the eye safety.

[0013] Disclosure of Invention

[0014] The objective of the invention is solved with the method in that electric charge of the at least one receiving element that is generated by the received electromagnetic echo signals is accumulated, after at least one predetermined time interval the accumulated electric charge of the at least one receiving element is compared with at least one predetermined eye-safety- charge-threshold, and if the comparison shows that the at least one accumulated electric charge has reached the at least one eye-safety-charge-threshold, an eye safety procedure is performed.

[0015] Electromagnetic echo signals that are received with at least one receiving element are converted into electric charge. The electric charge depends on the amount of electromagnetic radiation received by the at least one receiving element. The amount of 3 / 27 2022PF00195 electromagnetic radiation depends on the power of the electromagnetic echo signals and the time of the irradiation. Hence, the electric charge that is generated by the at least one receiving element depends on the power of the electromagnetic echo signals and the duration of accumulation.

[0016] According to the invention, the electric charge is accumulated within the predetermined time interval. The predetermined time interval specifies the duration of accumulation. The accumulated electric charge is compared to at least one predetermined eye-safety- charge-threshold. The at least one eye-safety-charge-threshold specifies a limit that is acceptable for the accumulated electric charge to ensure the eye safety when operating the LiDAR system. If the accumulated electric charge reaches the at least one eye-safety- charge-threshold, an eye safety procedure is performed to ensure the eye safety.

[0017] Since the monitoring of the eye safety is done immediately after the conversion of the electromagnetic echo signals into electric charge, it can be detected very quickly when the electromagnetic scanning signals endanger eye safety. This makes it possible to use the electromagnetic scanning signals with higher power. By increasing the power of the electromagnetic scanning signals, the detection range of the LiDAR system can be improved. In this way, the detection range of the LiDAR system can be improved while maintaining the eye safety.

[0018] Advantageously, at least one receiving element can be formed as a pixel. In this way, optical echo signals can be received with the at least one receiving element and converted into electric charge.

[0019] Advantageously, the at least one receiving device can comprise at least one imager chip. With an imager chip, several receiving elements, in particular pixels, can be formed. The receiving elements of the imager chip can be controlled and read out separately. Advantageously, the at least one receiving device can comprise at least one CCD chip. With a CCD chip an imager chip with at least one receiving element, in particular at least one pixel, can be formed.

[0020] Advantageously, at least one receiving device can comprise an array with several receiving elements. In this way, the electromagnetic echo signals can be received spatially 4 / 27 2022PF00195 resolved. The receiving elements can be arranged in at least one column and / or in at least one row and / or in at least one matrix of the array.

[0021] By use of at least one receiving element, in particular at least one pixel, electromagnetic signals such as light can be transformed into electric charge.

[0022] After a predetermined time interval the accumulated electric charge of the at least one receiving element is compared with at least one predetermined eye-safety-charge-threshold. If the comparison shows that the at least one accumulated electric charge has reached the at least one eye-safety-charge-threshold, an eye safety procedure is performed.

[0023] The accumulated electric charge can be compared direct with at least one predetermined eye-safety-charge-threshold. Alternatively, the accumulated electric charge can be compared indirect with at least one predetermined eye eye-safety-charge-threshold. “Indirect” in this sense means, that at least one electric charge value can be determined that characterizes the accumulated electric charge. The at least one electric charge value can be compared with at least one eye safety value that characterizes the eye-safety-charge- threshold.

[0024] Advantageously, for the comparison of the electric charge with the at least one eye- safety-charge-threshold, in particular for comparison of the electric charge value with the at least one eye safety value, at least one multiplexer can be used. In this way, the reaction time for detecting when the eye-safety-charge-threshold, in particular the eye safety value, has been reached can be reduced.

[0025] Advantageously, after a predetermined time interval at least one charge value can be determined based on the accumulated electric charge of the at least one receiving element. At least one charge value can be compared with at least one predetermined eye safety threshold value. If the comparison shows that the at least one charge value has reached the at least one eye safety threshold value, an eye safety procedure can be performed. 5 / 27 2022PF00195

[0026] The at least one charge value can quantify the electric charge. In this way, the electric charge can be compared with at least one eye safety threshold value by use of the at least one charge value.

[0027] Subsequent to the comparison of the electric charge, in particular electric charge value, the electric charge can be read out and quantified. For the read out of the electric charge at least one analog-to-digital converter can be used. In this way, the electric charge can be converted to digital values, e.g. electric charge values.

[0028] Advantageously, the electric charge can be embodied by at least one electrical quantity like charges, voltages, currents, capacitances or the like. In this way, the electric charges can be processed, in particular compared, by use of electric / electronic components or devices.

[0029] The values, in particular the charge values and eye safety threshold values, can be physical quantities, in particular electrical quantities like charges, voltages, currents, capacitances or the like. Means for carrying out the method for operating the LiDAR system can comprise means to compare values in form of physical quantities.

[0030] The values, in particular the charge values and the eye safety threshold values, may include electrical quantities, electrical signals and / or electrical values, for example based on digital values like bits. In this way, the values can be processed by electrical means for signal processing. Additionally or alternatively, the values, in particular the charge values and the eye safety threshold values, may include optical signals or values, for example based on qubits. In this way, the received signals can be processed by optical means for signal processing, for example, quantum processors.

[0031] The LiDAR system can be used on vehicles. A key functional characteristic of a vehicle is its ability to move. Vehicles can be motor vehicles. Advantageously, the LiDAR system can be used on land vehicles, and particular passenger cars, trucks, buses, motorcycles, drones, mobile robots, mobile machines, in particular construction or transport machines, such as cranes, excavators or the like, aircraft, and particular flying drones, and / or (underwater vehicles, in particular (under)water drones. The LiDAR system can also be 6 / 27 2022PF00195 used on vehicles that can be operated autonomously or semiautonomously. However, the LiDAR system is not limited to vehicles. It can also be used in stationary operation.

[0032] The LiDAR system can be used to detect stationary or moving objects, in particular vehicles, persons, animals, obstacles, road unevenness, in particular potholes or stones, road limitations, open spaces, in particular parking spaces, precipitations or the like.

[0033] According to a favorable embodiment, the receiving of electromagnetic echo signals can be triggered with at least one periodic receive demodulation signal and the electric charge can be accumulated in at least one storage means, in particular in at least one storage gate, in particular the receiving of electromagnetic echo signals can be triggered with a first periodic receive demodulation signal and with a second periodic receive demodulation signal, that has a phase shift of 180° from the first periodic receive demodulation signal, and the electric charge obtained due to triggering with the first receive demodulation signal can be accumulated in a first storage means and the electric charge obtained due to triggering with the second receive demodulation signal can be accumulated in a second storage means and / or at least one receive demodulation signal for triggering the receiving of the electromagnetic echo signals can be generated in coordination with at least one periodic transmit demodulation signal, with which the sending of the at least one electromagnetic scanning signal can be triggered. In this way, the electromagnetic echo signals can be received periodically dependent on the receive demodulation signal. So, the acquisition can be correlated to scanning signals that can be pulsed based on respective transmit demodulation signals.

[0034] Advantageously, the at least one receive demodulation signal and / or the at least one transmit demodulation signal can be an electric signal. In this way, electronic devices for signal generation can be used.

[0035] Advantageously, the demodulation signals, in particular the receive demodulation signals and / or the transmit demodulation signals, can be periodic signals, in particular square wave signals. In this way, the transmitting of scanning signals and / or the acquisition of 7 / 27 2022PF00195 echo signals can carried out periodically. Start and / or end of the transmission and / or the acquisition can be triggered by pulses of respective square wave signals.

[0036] Advantageously, the electric charge can be accumulated in at least one storage means. In this way, the electric charge can be accumulated over several periods of the at least one receive demodulation signal.

[0037] Advantageously, the at least one storage means can be a storage gate. In this way, the storage means can be formed by a corresponding circuit.

[0038] Advantageously, the receiving of electromagnetic echo signals can be triggered with a first periodic receive demodulation signal and with a second periodic receive demodulation signal. In this way, the echo signals can be received in two different phases of the demodulation signal. So, the signal-to-noise ratio can be improved.

[0039] Advantageously, the second periodic receive demodulation signal can have a phase shift of 180° from the first periodic receive demodulation signal. In this way, an overlap of the pulses can be avoided.

[0040] Advantageously, the electric charge obtained due to triggering with the first receive demodulation signal can be accumulated in a first storage means. The electric charge obtained due to triggering with the second receive demodulation signal can be accumulated in a second storage means. In this way, the results of the receiving of echo signals due to triggering with the first receive demodulation signal can be processed independently of the results of the receiving of echo signals due to triggering with the second receive demodulation signal. The results of the receiving of echo signals due to triggering with the first receive demodulation signal can be combined with the results of the receiving of echo signals due to triggering with the second receive demodulation signal after both are completed.

[0041] Advantageously, at least one receive demodulation signal can be generated in coordination with at least one periodic transmit demodulation signal, with which the transmission of the at least one electromagnetic scanning signal can be triggered. In this way, the sending of scanning signals and the receiving of echo signals can be correlated. 8 / 27 2022PF00195

[0042] The expressions “first” and “second” in connection with the receive demodulation signals, the storage means, in particular the storage gates, and the electric charges are used only for better distinction and assignment. They do not specify an order.

[0043] According to another favorable embodiment, the electric charges can be accumulated by use of at least one storage means, in particular at least one storage gate, in particular first electric charges obtained due to triggering with a first receive demodulation signal can be accumulated by use of a first storage means and second electric charges obtained due to triggering with a second receive demodulation signal can be accumulated by use of a second storage means. In this way, the results of the receiving of echo signals in different phases can be stored individually. The results can be combined later.

[0044] According to another favorable embodiment, at least two individual electric charges from at least two individual demodulation phases, in particular a first electric charge and a second electric charge, of the at least one receiving element can be combined, in particular added up, and the combination, in particular the sum, of the at least two electric charges can be compared with at least one predefined eye-safety-charge-threshold and / or at least one electric noise and at least one individual electric charge can be combined, in particular added up, and the combination, in particular the sum, can be compared with at least one predefined eye-safety-charge-threshold. In this way, reaching the eye safety threshold value can be determined more precisely.

[0045] Advantageously, at least two individual electric charges from at least two individual demodulation phases of the at least one receiving element can be combined. In this way, individual electric charges that were determined under different conditions, in particular in different demodulation phases, can be combined with each other. So, the accuracy of the total electric charge can be improved compared to the individual electric charges.

[0046] Advantageously, at least two individual electric charges from at least two individual demodulation phases of the at least one receiving element can be added up. In this way, the signal-to-noise ratio can be improved. 9 / 27 2022PF00195

[0047] Advantageously, a first electric charge and a second electric charge of the at least one receiving element can be combined, in particular added up. In this way, the total electric charge can be combined of two defined individual electric charges.

[0048] Advantageously, the at least two individual electric charges can be determined in different demodulation phases of the receiving of echo signals with the at least one receiving element. In this way, the signal-to-noise ratio can be improved.

[0049] The combination, in particular the sum, of the at least two electric charges can be compared with at least one predefined eye-safety-charge-threshold. In this way, the combined electric charge can be compared to the eye-safety-charge-threshold by use of only one comparison step.

[0050] Advantageously, at least one electric noise and at least one individual electric charge can be combined, in particular added up. The combination, in particular the sum, can be compared with at least one predefined eye-safety-charge-threshold. In this way, the accuracy of the comparison with the eye-safety-charge-threshold can be further improved.

[0051] Advantageously, the at least one electric noise can be determined in the same measurement as the individual electric charges. Alternative, the at least one electric noise can be determined in different measurements. The at least one electric noise can also be determined by delay of the sending of the at least one electromagnetic scanning signal after the activation of the at least one receiving element. The at least one electric noise can be determined by delay of the laser trigger after the shutter. The energy, in particular the energy of the electric noise, can be kept in separate storage, e.g. a copy of the storage level before the start of the trigger.

[0052] The at least one electric noise can indicate the noise acquired with a respective receiving element.

[0053] According to another favorable embodiment, the at least one receiving element can be activated to receive electromagnetic echo signals for the duration of a predefined integration time and the time interval to determine at least one charge value can be specified 10 / 27 2022PF00195 shorter or equal to the integration time. The integration time is limiting the time of receiving echo signals. The integration time can be limited to the expected time-of-flight required for a scanning signal and the respective reflected echo signal to scan a distance range of interest.

[0054] Advantageously, the time interval in which electric charge is accumulated can be specified shorter or equal to the integration time. In this way, the reaching of the eye-safety- charge-threshold can be detected more quickly. It is not necessary to wait for the entire integration time.

[0055] According to another favorable embodiment, at least one time interval and / or, if so, at least one integration time of activation of the at least one receiving element, can be defined based on a period of at least one demodulation signal, in particular based on a period of at least one receive demodulation signal and / or based on a period of at least one transmit demodulation signal. In this way, it is easier to define the at least one time interval and, if so, the at least one integration time. The start and / or the end of the at least one time interval can be triggered by corresponding edges of the at least one demodulation signal. Accordingly, the start and / or the end of the at least one integration time can be triggered by corresponding edges of the at least one demodulation signal.

[0056] Advantageously, at least one demodulation signal can be formed as a periodic sequence of pulses. Advantageously, at least one time interval and / or at least one integration time of activation can be defined based of a number of pulses of the at least one demodulation signal. In this way, the at least one time interval and / or the at least one integration time can be defined more clearly.

[0057] According to another favorable embodiment, the receiving device can comprise at least one array of receiving elements and the individual electric charges of at least two of the receiving elements, in particular of at least two adjacent receiving elements, can be combined and / or a combination of the individual electric charges of at least two of the receiving elements can be configured based on the irradiation of the array of receiving elements by echo 11 / 27 2022PF00195 signals. In this way, a monitoring of the eye safety can be based on more than one receiving element.

[0058] Advantageously, the individual electric charges of at least two adjacent receiving elements can be combined. In this way, clusters of receiving elements can be generated.

[0059] Advantageously, the combination of the individual electric charges of at least two of the receiving elements can be configured in particular based on the irradiation of the array of receiving elements by echo signals. In this way, the method for monitoring the eye safety can be configured in order to select a cluster or an area as a parameter for the eye-safety- charge-threshold. The formation of clusters or areas prevents that the eye safety procedure is carried out due to blooming targets in the monitoring area. A configurable area or cluster has the advantage to select the size of a target in the monitoring area in front of the LiDAR system based on a three-dimensional position and resolution of the receiving device.

[0060] According to another favorable embodiment, the eye safety procedure can comprise the stopping of sending of electromagnetic scanning signals, in particular the generating of at least one stop signal, in particular an eye safety flag, for a controlling means for a transmitting device of the LiDAR system, and / or the eye safety procedure can comprise the providing of at least one stop signal, in particular an eye safety flag, to at least one protection circuit for eye safety protection.

[0061] Advantageously, the eye safety procedure can comprise the stopping of the transmission of electromagnetic scanning signals. In this way, the danger to the eyes from electromagnetic scanning signals can be stopped immediately and safely.

[0062] Advantageously, the eye safety procedure can comprise the generating of at least one stop signal for a controller of a transmitting device of the LiDAR system. In this way, the transmission of electromagnetic scanning signals can be interrupted by use of the controller. 12 / 27 2022PF00195

[0063] Advantageously, the eye safety procedure can comprise the providing of at least one stop signal, in particular an eye safety flag, to at least one protection circuit for eye safety protection. In this way, appropriate measures can be taken by use of the protection circuit.

[0064] Advantageously, a stop signal can be the state of a flag, in particular an eye safety flag. In particular, a flag can have a default setting, for example “0”. As soon as the eye-safety- charge-threshold is reach, the flag can be set to a stop value, for example “1 ”.

[0065] According to another favorable embodiment, the at least one eye-safety-charge-threshold can be predefined as a fixed quantity and / or the at least one eye-safety-charge-threshold can be configured dependent in particular from an operating mode of the LiDAR system.

[0066] Advantageously, the at least one eye-safety-charge-threshold can be predefined as a fixed quantity. In this way, the LiDAR system can be configured more easily.

[0067] Advantageously, the at least one eye safety charge threshold can be configured dependent in particular from an operating mode of the LiDAR system. In this way, the monitoring of the eye safety can be carried out more precisely.

[0068] Advantageously, the LiDAR system can be operated in different operation modes, in particular a long-range detection mode and / or a medium-range detection mode and / or a short-range detection mode. In this way, the LiDAR system can be optimized for the respective range. In the long-range detection mode, the power of the transmitted scanning signals can be higher than in the medium-range detection mode or in the short-range detection mode.

[0069] Further, the objective of the invention is solved with the software in that the software comprises at least a portion of the means for carrying out a method according to the invention.

[0070] With software, at least a portion of the means for carrying out the method can be easily implemented in a suitable hardware. 13 / 27 2022PF00195

[0071] The means for carrying out the method according to invention can comprise means for controlling the sending of electromagnetic scanning signals. Further, the means can comprise means for controlling receiving elements.

[0072] Furthermore, the means for carrying out the method according to the invention can comprise means for accumulating electric charges of receiving elements.

[0073] Moreover, the means for carrying out the method according to the invention can comprise means for accumulating electric charges of receiving elements for predetermined time intervals.

[0074] In addition, the means for carrying out the method according to the invention can comprise means for comparing electric charges with eye-safety-charge-thresholds.

[0075] Further, the means for carrying out the method according to the invention can comprise means for performing eye safety procedures depending on comparisons of electric charges and eye-safety-charge-thresholds.

[0076] Furthermore, the objective of the invention is solved with the LiDAR system in that the LiDAR system comprises at least a portion of the means for carrying out a method according to the invention.

[0077] Advantageously, the means for carrying out the method can comprise at least one control and evaluation device. With the at least one control and evaluation device functions of the LiDAR system can be controlled and quantities are values obtained by use of the at least one receiving element can be processed. At least a portion of the software according to the invention can be formed by use of means of the at least one control and evaluation device.

[0078] At least a part of the means for carrying out the method according to the invention can be formed by software. In this way, in particular flow charts, programs, algorithms and the like for carrying out the method can be used. Additionally or alternatively, at least a portion M21 2022PF00195 of the means for carrying out the method according to the invention can be realized by hardware.

[0079] Moreover, the objective of the invention is solved with the driver assistance system by that the driver assistance system comprises at least a portion of the means for carrying out a method according to the invention.

[0080] According to the invention, the driver assistance system comprises at least one LiDAR system. With the at least one LiDAR system, at least one monitoring area in an environmental of the vehicle and / or inside the vehicle can be monitored. Information obtained with the at least one LiDAR system can be used with a control unit of the at least one driver assistance system for operating functions, in particular driving functions, of the vehicle autonomously or semiautonomously.

[0081] According to the invention, the driver assistance system comprises at least one LiDAR system, in particular at least one LiDAR system according to the invention. Advantageously, at least one LiDAR system of the driver assistance system, in particular of the driver assistance system according to the invention, can comprise at least a portion of means for carrying out the method according to the invention. Since the at least one LiDAR system is part of the driver assistance system, the means of the at least one LiDAR system are thus also part of the driver assistance system. This applies analogously with respect to means of the vehicle, which comprises at least one driver assistance system and / or at least one LiDAR system.

[0082] In addition, the objective of the invention is solved with the vehicle in that the vehicle comprises at least a portion of the means for carrying out a method according to the invention.

[0083] The vehicle comprises at least one LiDAR system. With the at least one LiDAR system, a monitoring area in the environment of the vehicle and / or a monitoring area inside the vehicle can be monitored. 15 / 27 2022PF00195

[0084] Advantageously, the vehicle can comprise at least one driver assistance system. With the at least one driver assistance system functions of the vehicle can be operated autonomously or semiautonomously.

[0085] Advantageously, at least one LiDAR system can be part of or connected to at least one driver assistance system. In this way, information obtained with the at least one LiDAR system can be transmitted to a control unit of the at least one driver assistance system. With the at least one driver assistance system information obtained from the at least one LiDAR system can be used for operating functions of the vehicle autonomously or semiautonomously.

[0086] Additionally or alternatively, at least a portion of the means for performing the method according to the invention can be realized separately from the at least one LiDAR system, for example with a control unit of the vehicle and / or a control unit of the driver assistance system.

[0087] Otherwise, the features and advantages shown in connection with the method according to the invention, the software according to the invention, the LiDAR system according to the invention, the driver assistance system according to the invention and the vehicle according to the invention and their respective advantageous configurations shall apply mutatis mutandis to each other and vice versa. The individual features and advantages can, of course, be combined with each other, whereby further advantageous effects can occur which go beyond the sum of the individual effects.

[0088] Brief Description of Drawings

[0089] The present invention together with the above-mentioned and other objects and advantages may best be understood from the following detailed description of the embodiments, but not restricted to the embodiments, wherein is shown schematically figure 1 a vehicle with a driver assistance system comprising a LiDAR system; figure 2 a diagram of the driver assistance system with a LiDAR system of figure 1 ; figure 3 a section of a receiving matrix of the LiDAR system of figure 1 ; figure 4 time diagrams of a transmit demodulation signal for triggering a transmitting device of the LiDAR system of figures 1 to 3, first receive demodulation 16 / 27 2022PF00195 signal and the second receive demodulation signal for triggering a receiving device of the LiDAR system; figure 5 a circuit for monitoring the eye safety of the LiDAR system of figures 1 to 3; figure 6 a circuit for the readout of the receiving matrix of the LiDAR system of figures 1 to 3; figure 7 a flowchart of a method for operating the LiDAR system of figures 1 to 3 according to a first embodiment; figure 8 a flowchart of a method for operating the LiDAR system of figures 1 to 3 according to a second embodiment.

[0090] In the drawings, equal or similar elements are referred to by equal reference numerals. The drawings are merely schematic representations, not intended to portray specific parameters of the invention. Moreover, the drawings are intended to depict only typical embodiments of the invention and therefore should not be considered as limiting the scope of the invention.

[0091] Embodiment(s) of Invention

[0092] Figure 1 shows a vehicle 10 in form of a passenger car in a front view. The vehicle 10 comprises a driver assistance system 12. By use of the driver assistance system 12 functions, for example driving functions, of the vehicle 10 can be operated autonomously or semiautonomously. Figure 2 shows a diagram of the driver assistance system 12.

[0093] The driver assistance system 12 comprises a LiDAR system 14 and a control unit 16. The control unit 16 can be used to autonomously or semiautonomously control functions of the vehicle 10 based on information that are obtained using the LiDAR system 14. The control unit 16 comprises hardware means, for example at least one processor, and software means, for example at least one software program.

[0094] The LiDAR system 14 is exemplarily configured as a flash LiDAR system 14. By way of example, the LiDAR system 14 is arranged in a front part of the vehicle 10. The LiDAR system 14 is directed in a monitoring area 18 in front of the vehicle 10. The LiDAR system 14 may also be arranged elsewhere on the vehicle 10 and oriented differently. The LiDAR system 14 can be used to determine object information, such as distance values, direction values, and / or velocity values that characterize distances, directions, and velocities of 17 / 27 2022PF00195 objects 20 relative to the vehicle 10 or relative to a reference point of the corresponding LiDAR system 14.

[0095] The objects 20 may be stationary or moving objects, for example, other vehicles, persons, animals, plants, obstacles, roadway irregularities, for example, potholes or stones, roadway boundaries, traffic signs, open spaces, for example, parking spaces, precipitation, or the like.

[0096] The LiDAR system 14 comprises, by way of example, a transmitting device 22, a receiving device 24 and a control and evaluation device 26.

[0097] The control and evaluation device 26 is exemplarily an electronic control and evaluation device 26, for example with one or more processors. The functions of the control and evaluation device 26 can be implemented centrally or decentrally by software and / or hardware. Parts of the functions of the control and evaluation device 26 may also be integrated in the transmitting device 22, the receiving device 24 and / or the control unit 16 of the driver assistance system 12.

[0098] The control and evaluation device 26 comprises means for generating transmit demodulation signals 28 and receive demodulation signals 30A and 30B. Figure 4 shows an example of a transmit demodulation signal 28, top, an example of a first receive demodulation signal 30A, middle, and an example of a second receive demodulation signals 30B, bottom. The transmit demodulation signal 28, the first receive demodulation signal 30A and the second receive demodulation signal 30B each are periodic electric signals, for example periodic sequences of square pulses. The transmit demodulation signal 28, the first receive demodulation signal 30A and the second receive demodulation signal 30B have the same period and pulse duration. The transmit demodulation signal 28 and the first receive demodulation signal 30A have the same phase. The second receive demodulation signal 30B has a phase shift of 180° with respect to the first receive demodulation signal 30A.

[0099] The transmitting device 22 comprises for example a laser diode. The transmitting device 22 can be controlled with the transmit demodulation signal 28 so that it sends electromagnetic scanning signals 32 in the form of laser pulses into the monitoring area 18. The 18 / 27 2022PF00195 transmitting device 22 further can comprise an optical system. The optical system can be used to expand the electromagnetic scanning signals 32 so that they simultaneously illuminate the monitoring area 18.

[0100] Electromagnetic scanning signals 32 reflected from an object 20 in the direction of the receiving device 24, which are referred to as echo signals 34 for better differentiation, can be received by the receiving device 24.

[0101] The receiving device 24 may optionally include means, such as optical systems, for directing the echo signals 34 to a receiving matrix 36 of the receiving device 24. Figure 3 shows a section of the receiving matrix 36 in a front view.

[0102] The receiving matrix 36 is formed, for example, with an imager chip. The receiving matrix 36 comprises several receiving elements 38. The receiving elements 38 may be referred to as “pixels”. The receiving elements 38 are arranged in a plurality of columns and a plurality of rows. Each four adjacent receiving elements 38, arranged in a square, form a receiving group 40. In figure 3, four of those receiving groups 40 are marked as examples. Each receiving group 40 comprises an arrangement of 2 x 2 receiving elements 38.

[0103] With each receiving group 40 an integration process 42 and an readout process 44 are performed, indicated for example in figure 7. The receiving elements 38 of the receiving groups 40 that have the same location within the respective receiving group 40 are controlled simultaneously in the whole receiving matrix 36. For example, the receiving elements 38 in the rows are controlled simultaneously during the integration process 42 and the receiving elements 38 in the columns are controlled simultaneously during the readout process 44.

[0104] Two storage means in form of storage gates 46A and 46B are assigned to each receiving element 38. The storage gates 46A and 46B are depicted in figures 5 and 6. The first storage gate 46A is controlled by the first receive demodulation signal 30A. The second storage gate 46B is controlled by the second receive demodulation signal 30B.

[0105] During the integration process 42, the storage gates 46A and 46B accumulate electric charges eA and eB created by the received echo signals 34, as shown in figure 5. Thereby, 19 / 27 2022PF00195 the first storage gate 46A accumulates first electric charges eA created by the received echo signals 34 during the square pulses of the first receive demodulation signal 30A. The second storage gate 46B accumulates second electric charges eB created by the received echo signals 34 during the square pulses of the second receive demodulation signal 30B.

[0106] The expressions “first” and “second” in connection with the receive demodulation signals 30A and 30B, the storage gates 46A and 46B and the electric charges eA and eB are used only for better distinction and assignment. They do not specify an order.

[0107] After the integration process 42, the readout process 44 can be started. During the readout process 44, the first electric charges eA stored in the first storage gate 46A and the second electric charges eB stored in the second storage gate 46B are read out as a difference eA - eB and converted to a single 12-bit digital value 48 and a 1 -bit saturation flag 50, as shown in figure 6. An analog-to-digital converter 52 is used for the conversion to the digital value 48. For the determination of the saturation flag 50, for example, a saturation comparator 54 can be used. Thereby, the electric charges eA and eB can be compared to a predefined saturation threshold THSAT.

[0108] Further, the receiving device 24 comprises a noise detection means 56, which is shown in figure 5. With the noise detection means 56 an electric noise N can be determined for the respective receiving element 38. For example, the noise detection means 56 can comprise a measurement procedure. The electric noise N can be determined in the same measurement as the individual electric charges eA and eB. Alternative, the electric noise N can be determined in different measurements. The electric noise N can also be determined by delay of the sending of the electromagnetic scanning signal 32 after the activation of the receiving elements 38. The electric noise N can be determined by delay of the laser trigger after the shutter. The energy, in particular the energy of the electric noise N, can be kept in a separate storage, e.g. a copy of the storage level before the start of the trigger.

[0109] Furthermore, the receiving device 24 comprises an eye safety comparator 58. With the eye safety comparator 58 a combination of the first electric charge eA, the second electric charge eB and the electric noise N can be compared with an eye-safety-charge-threshold THeye. For example, the combination of the first electric charge eA, the second electric 20 / 27 2022PF00195 charge ee and the electric noise N can be the sum of the electric charges eA and ee minus the electric noise N. The sum of the electric charges eA and ee minus the electric noise N can be denoted by the term (ea+ ee - N) in the following. The combination of the electric charges eA and ee minus the electric noise N, for example the sum of the electric charges eA and ee minus the electric noise N, can be called a total electric charge. The total electric charge can be compared with the eye-safety-charge-threshold THeye.

[0110] The eye safety comparator 58 can provide an eye safety flag 60 that depends on the comparison. The eye safety flag 60 can be a 1 -bit flag.

[0111] If the term (ea+ ee - N) reaches the eye-safety-charge-threshold THeye, a limit is reached that is acceptable for the accumulated electric charges eA and ee to ensure the eye safety when operating the LiDAR system 14. Reaching the limit indicates that the eye safety is at risk. In this case, the eye safety flag 60 can be set to “1 ”, for example. Otherwise, it can remain on the default value “0”.

[0112] If the eye safety flag 60 is set to “1 ”, an eye safety procedure 62 can be started. The eye safety procedure 62 is shown for example in figure 7 and 8. The eye safety procedure 62 comprise the stopping of the sending of scanning signals 32, for example. For this purpose, a stop signal for a controller means that controls the transmitting device 22 can be generated.

[0113] In figure 7 the method for operating the LiDAR system 14 according to a first embodiment is shown in a flowchart.

[0114] In a step 64 a detection of the noise N is performed by use of the noise detection means 56.

[0115] In a step 66 the integration process 42 is started. Thereby, a counter for an integration time TINT is started. The integration time TINT is shown in figure 4, for example. During the integration time TINT the transmitting device 22 is activated for sending scanning signals 32 and the receiving elements 38 are activated for receiving echo signals 34. 21 / 27 2022PF00195

[0116] Further, the transmit demodulation signals 28 and the first demodulation signals 30A are triggered. The second demodulation signals 30B triggered with a phase shift of 180°.

[0117] According to the transmit demodulation signals 28 the scanning signals 32 in form of laser pulses are sent into the monitoring area 18. For example, the power of the scanning signals 32 can be set high to perform a long distance measurement of about 100 m. During the integration time TINT the integration process 42 is performed, as described above.

[0118] After a predefined time interval 68 the sum of the accumulated first electric charges eA and the second electric charges eB minus the electric noise N, which is the term (ea+ eB - N), is compared in a step 70 with the eye-safety-charge-threshold THeye by use of the eye-safety comparator 58.

[0119] Figure 4 shows a sequence of several time intervals 68 as an example. For the sake of clarity, only the first four time intervals 68 are indicated. The time intervals 68 have the same length. Each time interval 68 is shorter than the integration time TINT. The time intervals 68 are correlated to the transmit demodulation signal 28 and the receive demodulation signals 30A and 30B, for example. For example, the length of each time interval 68 corresponds to the duration of the pulses of the transmit demodulation signal 28 and the receive demodulation signals 30A and 30B.

[0120] If in step 70 is found, that the sum of the accumulated first electric charges eA and the second electric charges eB minus the electric noise N, namely (ea+ eB - N), reaches the eye-safety-charge-threshold THeye, the eye safety flag 60 is set to “1 ” in a step 72.

[0121] After that, the eye safety procedure 62 is started. Thereby, the transmission of scanning signals 32 is stopped immediately.

[0122] Otherwise, if in step 70 is found, that the sum of the accumulated first electric charges eA and the second electric charges eB minus the electric noise N, namely (ea+ eB - N), is below the eye-safety-charge-threshold THeye, the eye safety flag 60 remains at “0” and in a step 74 it is proved, if the integration time TINT is expired. 22 / 27 2022PF00195

[0123] If in step 74 is found, that the integration time TINT is expired, the readout process 44 is performed as described above.

[0124] Otherwise, if in step 74 is found, that the integration time TINT is not expired, the integration process 42 continued for the next time interval 68.

[0125] As long as the sum of the accumulated first electric charges eA and the second electric charges ee minus the electric noise N, namely (ea+ ee - N), is below the eye-safety- charge-threshold THeye, the integration process 42 is continued and in each time interval 68, the sum of the accumulated first electric charges eA and the second electric charges ee minus the electric noise N is compared with the eye-safety-charge-threshold THeye. During the integration time TINT several time intervals 68 follow each other without gaps, as shown in figure 4.

[0126] The data that is obtained after the readout process 44 is used for processing object information about objects 18 that are detected with a LiDAR system 14. The object information can comprise information about distances, directions and / or velocities of the detected objects 18 relative to the LiDAR system 14 and / or relative to the vehicle 10. The object information that is obtained through the use of the LiDAR system 14 is transferred to the control unit 16 of the driver assistance system 12 and used for autonomous or semiau- tonomous operation of functions, for example driving functions, of the vehicle 10.

[0127] Figure 8 shows the method for operating the LiDAR system 14 according to a second embodiment. Those elements which are similar to those of the first embodiment of figure 7 are provided with the same reference signs. The second embodiment differs from the first embodiment in that the time interval 68 corresponds to the integration time TINT. The step 74 to check, if the integration time TINT has expired, is performed as part of the integration process 42. The integration process 42 is continued for the duration of the integration time TINT. Only after expiration of the integration time TINT, in the step 70 the sum of the accumulated first electric charges eA and the second electric charges es minus the electric noise N, namely (ea+ es - N), is compared with the eye-safety-charge-threshold THeye. 23 / 27 2022PF00195

[0128] If in step 70 is found, that the sum of the accumulated first electric charges eA and the second electric charges ee minus the electric noise N, namely (ea+ ee - N), reaches the eye-safety-charge-threshold THeye, the eye safety flag 60 is set to “1 ” in the step 72.

[0129] After that, the eye safety procedure 62 is started. Thereby, the transmission of scanning signals 32 is stopped immediately.

[0130] Otherwise, if in step 70 is found, that the sum of the accumulated first electric charges eA and the second electric charges ee minus the electric noise N, namely (ea+ ee - N), is below the eye-safety-charge-threshold THeye, the eye safety flag 60 remains at “0” and the readout process 44 is performed as described above.

Claims

24 / 27 2022PF00195Claims1 . Method for operating a LiDAR system (14), in particular for operating a LiDAR system (14) of a vehicle (10), in which at least one electromagnetic scanning signal (32) is sent into a monitoring area (18) by use of at least one transmitting device (22) of the LiDAR system (14), at least one receiving element (38) of a receiving device (24) of the LiDAR system (14) is activated to receive electromagnetic echo signals (34), if any, that originate from electromagnetic scanning signals (32) that are reflected in the monitoring area (18), characterized in that electric charge (eA, ee) of the at least one receiving element (38) that is generated by the received electromagnetic echo signals (34) is accumulated, after at least one predetermined time interval (68) the accumulated electric charge (eA, ee) of the at least one receiving element (38) is compared with at least one predetermined eye-safety-charge-threshold (Theye), and if the comparison shows that the at least one accumulated electric charge (eA, ee) has reached the at least one eye-safety-charge-threshold (Theye), an eye safety procedure (62) is performed.

2. Method according to claim 1 , characterized in that the receiving of electromagnetic echo signals (34) is triggered with at least one periodic receive demodulation signal (30A, 30B) and the electric charge (eA, 6B) is accumulated in at least one storage means (46A, 46B), in particular in at least one storage gate, in particular the receiving of electromagnetic echo signals (34) is triggered with a first periodic receive demodulation signal (30A) and with a second periodic receive demodulation signal (30B), that has a phase shift of 180° from the first periodic receive demodulation signal (30A), and the electric charge (OA) obtained due to triggering with the first receive demodulation signal (30A) is accumulated in a first storage means (46A) and the electric charge (es) obtained due to triggering with the second receive demodulation signal (30B) is accumulated in a second storage means (46B) and / or at least one receive demodulation signal (30A, 30B) for triggering the receiving of the electromagnetic echo signals (34) is generated in coordination with at least one periodic transmit demodulation signal (28), with which the sending of the at least one electromagnetic scanning signal (32) is triggered.25 / 27 2022PF001953. Method according to claim 2, characterized in that the electric charges (eA, ee) are accumulated by use of at least one storage means (46A, 46B), in particular at least one storage gate, in particular first electric charges (BA) obtained due to triggering with a first receive demodulation signal (30A) are accumulated by use of a first storage means (46A) and second electric charges (es) obtained due to triggering with a second receive demodulation signal (30B) are accumulated by use of a second storage means (46B).

4. Method according to one of the previous claims, characterized in that at least two individual electric charges (eA, es) from at least two individual demodulation phases, in particular a first electric charge (OA) and a second electric charge (es), of the at least one receiving element (38) are combined, in particular added up, and the combination, in particular the sum, of the at least two electric charges (eA, es) is compared with at least one predefined eye-safety-charge-threshold (Theye) and / or at least one electric noise (N) and at least one individual electric charge (eA, es) are combined, in particular added up, and the combination, in particular the sum, is compared with at least one predefined eye-safety-charge-threshold (Theye).

5. Method according to one of the previous claims, characterized in that the at least one receiving element (38) is activated to receive electromagnetic echo signals (34) for the duration of a predefined integration time (TINT) and the time interval (68) to determine at least one charge value is specified shorter or equal to the integration time (TINT).

6. Method according to 1 of the previous claims, characterized in that at least one time interval (68) and / or, if so, at least one integration time (TINT) of activation of the at least one receiving element (38), is defined based on a period of at least one demodulation signal (30A, 30B, 28), in particular based on a period of at least one receive demodulation signal (30A, 30B) and / or based on a period of at least one transmit demodulation signal (28).

7. Method according to 1 of the previous claims, characterized in that26 / 27 2022PF00195 the receiving device (24) comprises at least one array (36 of receiving elements (38) and the individual electric charges (eA, ee) of at least two of the receiving elements (38), in particular of at least two adjacent receiving elements (38), are combined and / or a combination of the individual electric charges (eA, ee) of at least two of the receiving elements (38) is configured based on the irradiation of the array (36) of receiving elements (38) by echo signals (34).

8. Method according to 1 of the previous claims, characterized in that the eye safety procedure (62) comprises the stopping of sending of electromagnetic scanning signals (32), in particular the generating of at least one stop signal, in particular an eye safety flag (72), for a controlling means for a transmitting device (22) of the LiDAR system (14), and / or the eye safety procedure (62) comprises the providing of at least one stop signal, in particular an eye safety flag (72), to at least one protection circuit for eye safety protection.

9. Method according to one of the previous claims, characterized in that, the at least one eye-safety-charge-threshold (Theye) is predefined as a fixed quantity and / or the at least one eye-safety-charge-threshold (Theye) is configured dependent in particular from an operating mode of the LiDAR system (14).

10. Software that comprises at least a portion of the means for carrying out a method for operating a LiDAR system (14), in particular for operating a LiDAR system (14) of a vehicle (10), characterized in that the software comprises at least a portion of the means for carrying out a method according to one of the claims 1 to 9.11 . LiDAR system (14), in particular a LiDAR system (14) for a vehicle (10), that comprises at least one transmitting device (22) for sending electromagnetic scanning signals (32), at least one receiving device (24) with at least one receiving element (38) for receiving electromagnetic signals (34), characterized in that the LiDAR system (14) comprises at least a portion of the means for carrying out a method according to one of the claims 1 to 9.27 / 27 2022PF0019512. Driver assistance system (12) with at least one LiDAR system (14), the LiDAR system (14) comprises at least one transmitting device (22) for transmitting electromagnetic scanning signals (32), at least one receiving device (24) with at least one receiving element (38) for receiving electromagnetic signals (34), characterized in that the driver assistance system (12) comprises at least a portion of the means for carrying out a method according to one of the claims 1 to 9.

13. Vehicle (10) with at least one LiDAR system (14), the LiDAR system (14) comprises at least one transmitting device (22) for transmitting electromagnetic scanning signals (32), at least one receiving device (24) with at least one receiving element (38) for receiving electromagnetic signals (34), characterized in that the vehicle (10) comprises at least a portion of the means for carrying out a method according to one of the claims 1 to 9.

Images